Identity Header Error Handling

Status of This Memo

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Table of Contents

1. Introduction

[RFC8224] in Section 6.2.2 discusses future specifications for enhancement of how errors are communicated and the handling of multiple identity headers. This specification provides some additional mechanisms for solutions to address these problems.¶

In some deployments of STIR and specifically using SIP [RFC3261] as defined by [RFC8224], one issue with the current error handling, specifically with the use of the defined 4xx error responses, is that when an error occurs with the verification of the identity header or the PASSporT contained in the identity header and a 4xx response is returned, the call is then terminated. It may be the case that the policy for handling errors might be that calls should continue even if there is a verification error, in the case of, for example inadvertent errors, however the authentication service should still be notified of the error so that corrective action can be taken. This specification will discuss the use of reason header in subsequent provisional (1xx) responses in order to accomplish this.¶

For the handling of multiple identity headers and the potential situation that some of the identity headers in a call may pass verification but others may have errors, this document provides a mechanism to add an identifier so that the authentication service can identify which identity header is being referred to in the case of an error.¶

2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶

3. Use of provisional error responses to signal errors without terminating the call

In cases where local policy dictates that a call should not terminate when any verification errors, including errors described in [RFC8224] Section 6.2.2, then the verification service SHOULD include the error response code and reason phrase in a Reason header field, defined in [RFC3326], in the next provisional or final response sent to the authentication service.¶

Example Reason header field:¶

Reason: SIP ;cause=436 ;text="Bad Identity Info"

4. Handling of errors when there is multiple identity headers

In cases where a SIP message includes multiple identity headers and one or more of those identity headers has errors the verification service SHOULD include the error response code and reason phrase in a Reason header field, defined in [RFC3326], in the next provisional or final response sent to the authentication service. The reason cause SHOULD represent at least one of the errors that occurred with one of the identity headers, but in order to identify each of the associated identity headers that had errors the body of the response should include a multipart MIME with each section including the PASSporT of the corresponding identity header.¶

Example Reason header field with multipart MIME body:¶

Reason: SIP ;cause=436 ;text="Bad Identity Info"

Content-Type: multipart/mixed; boundary=boundary1
Content-Length: ...

--boundary1

Content-Type: application/passport

eyJhbGciOiJFUzI1NiIsInR5cCI6InBhc3Nwb3J0IiwieDV1I \
joiaHR0cHM6Ly9jZXJ0LmV4YW1wbGUub3JnL3Bhc3Nwb3J0LmNlciJ9.eyJ \
kZXN0Ijp7InVyaSI6WyJzaXA6YWxpY2VAZXhhbXBsZS5jb20iXX0sImlhdC \
I6IjE0NDMyMDgzNDUiLCJvcmlnIjp7InRuIjoiMTIxNTU1NTEyMTIifX0.r \
q3pjT1hoRwakEGjHCnWSwUnshd0-zJ6F1VOgFWSjHBr8Qjpjlk-cpFYpFYs \
ojNCpTzO3QfPOlckGaS6hEck7w

--boundary1

Content-Type: application/passport

eyJhbGciOiJFUzI1NiIsInR5cCI6InBhc3Nwb3J0IiwieDV1I \
joiaHR0cHM6Ly9jZXJ0LmV4YW1wbGUub3JnL3Bhc3Nwb3J0LmNlciJ9.eyJ \
kZXN0Ijp7InVyaSI6WyJzaXA6YWxpY2VAZXhhbXBsZS5jb20iXX0sImlhdC \
I6IjE0NDMyMDgzNDUiLCJvcmlnIjp7InRuIjoiMTIxNTU1NTEyMTIifX0.r \
q3pjT1hoRwakEGjHCnWSwUnshd0-zJ6F1VOgFWSjHBr8Qjpjlk-cpFYpFYs \
ojNCpTzO3QfPOlckGaS6hEck7w

5. Acknowledgements

Would like to thank David Hancock for help to identify these error scenarios and Jon Peterson for helpful feedback.¶

6. Security Considerations

TBD¶

Author's Address